^^2 SCIENCE IN AFRICA 



without great difficulty, after, but not until, the major animal 

 diseases are under control. 



The following paragraphs in which the major diseases are dis- 

 cussed, are intended to be considered in conjunction with other 

 parts of this volume in which special studies bearing on the prob- 

 lems are outlined, namely Chapter VI, section on pasture research, 

 Chapter VIII, sections on animal ecology and conservation of 

 wild animals, and Chapter X, sections on tsetse flies, insects and 

 ticks in relation to diseases of stock. 



Only a small part of the vast literature on animal diseases can 

 be mentioned here as illustrative of the kind of work in progress. 

 The most complete and up-to-date work for general reference 

 appears to be the three volumes by G. Curasson (1936) in which 

 full bibliographies are given for all known 'exotic' animal diseases. 



In general it may be claimed that many of the principal diseases 

 are now controllable: horsesickness, blue-tongue, redwater, 

 gallsickness, anthrax, black quarter, and various other diseases 

 can be controlled by immunization. Rinderpest is still a major 

 problem in some parts of Africa, but with the aid of vaccination 

 it too can be kept in check; the Union of South Africa, and the 

 Rhodesias, as well as other territories, are entirely free from this 

 dreaded disease. No satisfactory method of immunization has 

 been devised against east coast fever, but the disease is controlled 

 in many parts of Africa by means of dipping to eradicate the tick 

 vectors, and quarantine. Dipping has brought untold benefits to 

 stock farmers in the Union of South Africa and other territories, 

 in many parts of which animal farming would be impossible with- 

 out it. Even in many native areas dipping is now employed on a 

 large scale. With the elimination of major diseases, numerous 

 minor diseases, some peculiar to the tropics. East Africa in particu- 

 lar, and some common in Europe and other countries, assume a 

 relatively more important position. The direction of research is 

 consequently changed, and investigations are now being made into 

 sterility, abortion, catarrh of cattle, respiratory diseases of sheep, 

 deficiency diseases, etc. 



SOUTHERN AFRICA 



In the understanding and control of many diseases the work of 



